Virtual camera position for head mounted display

ABSTRACT

A display provides display light to an eyebox area. A reflective layer receives the display light from the display and redirects the display light to the eyebox area. The reflective layer receives scene light from an external environment of the device and redirects the scene light to a camera for capturing scene images. The camera is positioned a first distance from the reflective layer that is approximately the same as a second distance between the reflective layer and the eyebox area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. non-provisional applicationSer. No. 16/143,411, entitled “VIRTUAL PUPIL CAMERA IN HEAD MOUNTEDDISPLAY” filed Sep. 26, 2018, which is hereby incorporated by reference.

TECHNICAL FIELD

This disclosure relates generally to optics and in particular to headmounted displays.

BACKGROUND INFORMATION

In Virtual Reality (VR), Mixed Reality (MR), and Augment Reality (AR),there may be contexts when a wearer of a head mounted display (HMD)should be aware of their physical surroundings. In AR and MR, a wearerof a HMD may be able to view scene light of an external physicalenvironment while also viewing virtual images presented on a display ofthe HMD. In VR, scene light from the external environment is oftenpurposely blocked out from the view of a wearer of an HMD to increase“presence.” Still, a variety of techniques have been developed to assista wearer of an HMD to be more aware of their surroundings. However, manyof these techniques are quite flawed.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the invention aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified.

FIG. 1 illustrates an example head mounted display (HMD) that includes acamera to image an external environment of the HMD.

FIG. 2 illustrates a cut away view of an HMD that includes a display andan optical assembly configured to direct display light to an eyeboxarea.

FIGS. 3A-3D illustrates an example view of an HMD system that includes afolded optical path and a camera positioned in a virtual pupil positionof the eyebox area, in accordance with embodiments of the disclosure.

FIG. 4 illustrates an example top or side view of an HMD system thatincludes two reflective surfaces and a camera positioned in a virtualpupil position of the eyebox area, in accordance with embodiments of thedisclosure.

FIG. 5 illustrates an example top view of an HMD system that includes asupport member and a camera positioned in a virtual pupil position ofthe eyebox area, in accordance with embodiments of the disclosure.

FIG. 6 illustrates an example circuit block diagram of a system that maybe incorporated into an HMD, in accordance with embodiments of thedisclosure.

DETAILED DESCRIPTION

Embodiments of a virtual pupil position for an HMD camera are describedherein. In the following description, numerous specific details are setforth to provide a thorough understanding of the embodiments. Oneskilled in the relevant art will recognize, however, that the techniquesdescribed herein can be practiced without one or more of the specificdetails, or with other methods, components, materials, etc. In otherinstances, well-known structures, materials, or operations are not shownor described in detail to avoid obscuring certain aspects.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments.

The disclosure includes an HMD having a camera positioned in a virtualpupil position of an eyebox area for a wearer of the HMD that improvesthe spatial awareness of a user of the HMD. Since the camera ispositioned to image the external environment of the HMD from a virtualpupil position that is approximately the same as the eye of a wearer ofthe HMD, images from the camera (or portions of those images) that arepresented to the user with the display of the HMD are from the correctperspective.

Conventionally, HMDs may have one or more “tracking” cameras that aremounted on the outside of the HMD to image the external environment.Those images may be used to provide the user cues (e.g. presented on thedisplay of the HMD) as to whether they will encounter a physical objectas they move through physical space. For objects in the far-field, theperspective of an external camera may be quite similar to theperspective of the eye of the user. When an object is in the far-field,the “angle-space” for the camera and the eye may be almost the same.However, for physical objects in the near-field (e.g. closer than 3meters), an offset in the perspective of an external camera from the eyeof the user may cause substantial errors in the spatial awareness of theuser in a physical environment because the angle-space is substantiallydifferent.

In embodiments of the disclosure, the camera is positioned to have thesame or very similar perspective as the eye of the user if the user wasviewing the same scene as the camera. In contexts such as “pass-through”virtual reality, images or portions of images captured by the camera maybe presented to the user on the display of an HMD. When a user interactswith objects in the physical world, having the outward facing cameracapture images from a pupil position that is similar to the eye of theuser allows the user to interact with objects in the physical world byviewing the images of those objects on the display of the HMD. In anembodiment, a camera is mounted facing outward on the front an HMD and alens assembly in the front of the camera provides a folded optical pathso that the camera has a virtual pupil position of an eye of a user ofthe HMD. In an embodiment, the camera is positioned a distance from amirror (within the headset) that is approximately the same distance asthe eye so that the virtual position of the camera simulates theposition (and perspective) of an eye of a wearer of the HMD. In anembodiment, a mirror is placed on the front of a headset and the camerais positioned in front of the mirror pointing back at the mirror wherethe camera is offset from the mirror by the same distance that the eyeis offset from the display. These and other embodiments are described indetail below in connection with FIGS. 1-6.

FIG. 1 illustrates an example head mounted display (HMD) 100 thatincludes a camera to image an external environment of HMD 100. In FIG.1, camera 147 is illustrated in a conventional position for imaging theexternal environment of HMD 100. The illustrated example HMD 100includes a top structure 141, a rear securing structure 143, and a sidestructure 142 attached with a viewing structure 140. The illustrated HMD100 is configured to be worn on a head of a user of the HMD. In oneembodiment, top structure 141 includes a fabric strap that may includeelastic. Side structure 142 and rear securing structure 143 may includea fabric as well as rigid structures (e.g. plastics) for securing theHMD to the head of the user. HMD 100 may optionally include earpiece(s)120 configured to deliver audio to the ear(s) of a wearer of HMD 100.

In the illustrated embodiment, viewing structure 140 includes aninterface membrane 118 for contacting a face of a wearer of HMD 100.Interface membrane 118 may function to block out some or all ambientlight from reaching the eyes of the wearer of HMD 100.

Example HMD 100 also includes a chassis for supporting hardware of theviewing structure 140 of HMD 100. Hardware of viewing structure 140 mayinclude any of processing logic, wired and/or wireless data interfacefor sending and receiving data, graphic processors, and one or morememories for storing data and computer-executable instructions. In oneembodiment, viewing structure 140 may be configured to receive wiredpower. In one embodiment, viewing structure 140 is configured to bepowered by one or more batteries. In one embodiment, viewing structure140 may be configured to receive wired data including video data. In oneembodiment, viewing structure 140 is configured to receive wireless dataincluding video data.

Viewing structure 140 may include a display for directing display lightto a wearer of HMD 100. The display may include an LCD, an organic lightemitting diode (OLED) display, micro-LED display, quantum dot display,pico-projector, or liquid crystal on silicon (LCOS) display fordirecting image light to a wearer of HMD 100.

FIG. 2 illustrates a cut away view of an HMD 200 that includes a display210 and an optical assembly 230 configured to direct display light 211to an eyebox area 290. In FIG. 2, camera 147 is offset from an eyeboxarea by an offset distance having a depth “z”. Optical assembly 230 ispositioned to receive the display light 211 and direct the display light211 to eye 202 as image light 213. Optical assembly 230 may beconfigured to allow eye 202 of a wearer of HMD 200 to focus on a virtualimage displayed by display 210. Although FIG. 2 only illustrates one eye202, an HMD may have a display 210 (or a portion of a shared display)and an optical assembly 230 for each eye of the user of the HMD.

In FIG. 2, camera 147 is offset from eyebox area 290 by an offsetdistance having a depth “z”. In the context of pass-through VR, imagesfrom camera 147 may be presented to the user of the HMD on display 210to give the user a sense of their physical environment without the needto remove the HMD from their head. However, if a user attempted to graspan object that was 1 meter away (based on the camera images rendered todisplay 210), the reach of the user may be off by the distance “z”because the perspective of camera 147 is offset by depth distance “z”from the eyebox area 290.

FIG. 3A illustrates an example top view of an HMD system 300 thatincludes a folded optical path and a camera positioned in a virtualpupil position of the eyebox area 390, in accordance with embodiments ofthe disclosure. System 300 includes a display 310, a lens element 393,camera 347, a first optical layer 371, and a second optical layer 372.Lens element 393 is configured to focus display light 311 to eyebox area390 for an eye 202 of a user of an HMD. First optical layer 371 is atleast partially reflective and second optical layer 372 is also at leastpartially reflective. In one embodiment, first optical layer 371includes a reflective polarizer that reflects a first polarizationorientation of incident light (e.g. vertically oriented linearlypolarized light) and transmits (passes) a second polarizationorientation of incident light that is orthogonal to the firstpolarization orientation (e.g. horizontally oriented linearly polarizedlight). In one embodiment, second optical layer 372 includes partiallymirrored surfaces that passes a portion of incident light (e.g. passesapproximately fifty percent of incident light) and reflects theremaining portion of incident light. First optical layer 371 is disposedbetween display 310 and second optical layer 372.

Camera 347 is oriented to capture scene images of incoming scene lightpropagating along a folded optical path 391 that includes reflecting offthe first optical layer 371 and reflecting off the second optical layer372. Without an obstruction from an HMD and/or display, eye 202 may havea view 341 of the external world. Camera 347 is configured to captureimages of at least a portion of that view 341 via scene lightpropagating along example folded optical path 391. In the illustratedembodiment, the first optical layer 371 is spaced a first distance Z₁395 from second optical layer 372 and eyebox area 390 is spaced a seconddistance Z₂ 396 from display 310. The second distance Z₂ 396 may beapproximately three times more than the first distance Z₁ 395 so thatthe optical path length for a given photon of incident scene lightpropagating along optical path 391 would be a same length as the photonencountering eyebox area 390. Therefore, camera 347 is disposed in avirtual pupil position of eyebox 390 with respect to the incoming scenelight. It is understood that FIG. 3A is illustrated to show the functionof system 300 and may not be drawn to scale. Camera 347 may besignificantly smaller and optical layer 371 may be disposed much closerto display 310, in a manufactured HMD that incorporates system 300.

FIG. 3B illustrates a plan view of an example optical layer 371 thatincludes an aperture void 374 for the camera 347 to receive scene lightto capture images of an external environment of the HMD, in accordancewith embodiments of the disclosure. Aperture void 374 may be in a middleof optical layer 371. The middle of aperture void 374 may be alignedwith a center of display 310. Camera 347 may be aligned with an axisrunning through the middle of the display 310 where the axis isorthogonal to a pixel plane (defined by two-dimensional pixel rows andcolumns) of the display 310.

FIG. 3C illustrates an example optical assembly 379 that includesoptical layers 371 and 372, in accordance with embodiments of thedisclosure. Optical assembly 379 may be positioned in front of camera347, in some embodiments. In FIG. 3C, optical layer 371 is illustratedas a reflective polarizer that reflects a first polarization orientationof incident light (e.g. vertically oriented linearly polarized light)and transmits (passes) a second polarization orientation of incidentlight that is orthogonal to the first polarization orientation (e.g.horizontally oriented linearly polarized light). Also in FIG. 3C,optical layer 372 is illustrated as a partially reflective layer thatpasses a portion of incident light (e.g. passes approximately fiftypercent of incident light) and reflects the remaining portion ofincident light. Example optical assembly 379 also includes aquarter-waveplate 381 disposed between the first optical layer 371 andthe second optical layer 372. Optical assembly 379 also includes acircular polarizer 382, and the second optical layer 372 is disposedbetween the quarter-waveplate 381 and the circular polarizer 382.Optical elements 372, 381, and 382 may be sized the same as reflectivepolarizer 371. Quarter-waveplate 381 may be coupled to partiallyreflective layer 372 or reflective polarizer 371. Circular polarizer 382may be coupled to partially reflective layer 372.

In operation, scene light 351 propagating along optical path 391encounters circular polarizer 382. Scene light 351 may be scattered andunpolarized. Circular polarizer 382 passes circularly polarized light352. In the illustrated embodiment, light 352 is illustrated asright-hand circularly polarized light 352. Light 352 encounterspartially reflective layer 372 and a portion of the light 352 isreflected by partially reflective layer 372 (not illustrated), while theremaining portion passes through layer 372 as right-hand circularlypolarized light 353. Quarter-waveplate 381 is configured to convertcircular polarization to linear polarized light 354. In the illustratedembodiment, linearly polarized light 354 is illustrated as verticallyoriented linearly polarized light 354. Light 354 reflects off ofreflective polarizer 371 as vertically oriented linearly polarized light355 since reflective polarizer 371 is configured to reflect verticallyoriented linearly polarized light and pass horizontally orientedlinearly polarized light, in FIG. 3C. Light 355 encountersquarter-waveplate 381 and is converted to right-hand circularlypolarized light 356. Light 356 encounters partially reflective layer 372and a portion of light 356 is reflected as left-hand circularlypolarized light 357. Light 357 encounters quarter-waveplate 381 and isconverted to horizontally oriented linearly polarized light 358. Inembodiments where optical layer 371 includes a hole such as aperturevoid 374, light 358 will not encounter reflective polarizer 371 beforebecoming incident on an image sensor (e.g. a CMOS image sensor) ofcamera 347. In other embodiments, light 358 may encounter reflectivepolarizer 371 and be passed by reflective polarizer 371 to camera 347because reflective polarizer 371 is configured to pass horizontallyoriented linearly polarized light, in the illustrated embodiment.

FIG. 3D illustrates an example optical assembly 399 that may be utilizedinstead of optical assembly 379 of FIG. 3C, in accordance withembodiments of the disclosure. FIG. 3D includes reflective polarizer 386as the first optical layer while the second optical layer is a mirror329, in FIG. 3D. Mirror 329 has a void that functions as an aperturevoid 398 for camera 347 so that light that would otherwise be reflectedby mirror 329 becomes incident on camera 347. Example optical assembly379 also includes quarter-waveplate 387 disposed between the firstoptical layer (reflective polarizer 386) and the second optical layer(mirror 329 in FIG. 3D). Quarter-waveplate 387 may be coupled to mirror329 or reflective polarizer 386.

In operation, scene light 322 propagating along optical path 321encounters reflective polarizer 386. Scene light 322 may be scatteredand unpolarized. Reflective polarizer 386 is configured to pass a firstlinear polarization of light (e.g. vertically oriented linearlypolarized light) and reflect a second linear polarization of light (e.g.horizontally oriented linearly polarized light) that is orthogonal tothe first linear polarization of light. In the illustrated embodiment ofFIG. 3D, reflective polarizer 386 is configured to pass verticallyoriented linearly polarized light of scene light 322 as verticallypolarized light 323. Light 323 encounters quarter-waveplate 387 and isconverted to right-hand circularly polarized light 324, in theillustrated embodiment of FIG. 3D. Light 324 reflects off of mirror 329as left-hand circularly polarized light 325 and is converted tohorizontally polarized light 326 by quarter-waveplate 387. Light 326 isreflected by reflective polarizer 386 as horizontally polarized light327 since reflective polarizer 386 is configured to reflect horizontallypolarized light, in the illustrated embodiment. Quarter-waveplate 387converts light 327 into left-hand circularly polarized light 328 whichpropagates through aperture void 398 to become incident on camera 347.

FIG. 4 illustrates an example top or side view of an HMD system 400 thatincludes two reflective surfaces and camera positioned in a virtualpupil position of the eyebox area 490, in accordance with embodiments ofthe disclosure. System 400 includes a display 310, a lens element 493,camera 347, and reflective layer 471. Reflective layer 471 may be angledapproximately 45 degrees in relation to the display 310 andapproximately 45 degrees in relationship to the camera 347. Lens element493 is configured to focus display light 411 to eyebox area 490 for aneye 202 of a user of an HMD. Reflective layer 471 may be a mirroredsurface made of metal. Reflective layer 471 may have a first reflectivesurface 472 disposed opposite a second reflective surface 473. Surface472 and 473 may be opposite sides of a same layer of metal.

In FIG. 4, display 310 emits display light 411 and display light 411 isredirected to the eyebox area 490 by first reflective surface 472. Scenelight 491 from an external environment of the HMD is received by secondreflective surface 473 and redirected to camera 347 for capturing sceneimages. Camera 347 may be positioned a first distance 495 from a middleof the reflective layer 471 that is approximately the same as a seconddistance 496 between reflective layer 471 and the eyebox area 490.

Without an obstruction from reflective layer 471, eye 202 may have aview 441 of the external world. Camera 347 is configured to captureimages of at least a portion of that view 441 by capturing imagesredirected by reflective layer 471. Since camera 347 is positioned thesame distance or approximately the same distance from the middle ofreflective layer 471 as eyebox area 490, camera 347 provides a virtualpupil position that is approximately the same as the position of eyeboxarea 490, as shown in FIG. 4.

FIG. 5 illustrates an example top view of an HMD system 500 thatincludes a support member 577 and a camera positioned in a virtual pupilposition of the eyebox area 590, in accordance with embodiments of thedisclosure. System 500 includes a display 310, a lens element 593,camera 347, and a reflective layer 571. Lens element 593 is configuredto focus display light 511 to eyebox area 590 for an eye 202 of a userof an HMD. Reflective layer 571 may be a mirrored surface made of metal.Display 310 is configured to provide display light 511 from a frontsideof the display 310. The reflective layer 571 is disposed on a backsideof display 310 that is opposite of the frontside. A pixel plane ofdisplay 310 may be parallel to a two-dimensional plane that thereflective layer 571 is disposed on.

In FIG. 5, display 310 emits display light 511 for presenting images tothe eye(s) of a user of HMD system 500. Scene light 591 from an externalenvironment of the HMD is received by reflective layer 571 andredirected to camera 347 for capturing scene images. Camera 347 isoriented to capture scene images of scene light 591 reflective fromreflective layer 571. Support member 577 supports camera 347 and extendscamera 347 a distance 596 from reflective layer 571 to allow camera 347to capture scene images reflecting off the reflective layer 571. HMDviewing structure 540 is coupled to reflective layer 571, in FIG. 5. Animaging field that camera 347 is configured to capture images in may bethe same size as the pixel array of display 310. Camera 347 ispositioned a distance 596 from reflective layer 571 that is the same orapproximately the same as a distance 595 between reflective layer 571and eyebox area 590. Since camera 347 is positioned approximately thesame distance from the middle of reflective layer 571 as eyebox area590, camera 547 provides a virtual pupil position that is approximatelythe same as a position of eyebox area 590 with respect to scene light591, as shown in FIG. 5. Without an obstruction from display 310, eye202 may have a view 541 of the external world. Camera 347 is configuredto capture images of at least a portion of that view 541 by capturingimages redirected by reflective layer 571.

FIG. 6 illustrates an example circuit block diagram of a system 600 thatmay be incorporated into an HMD, in accordance with embodiments of thedisclosure. System 600 includes processing logic 630, display 310,camera 347, media 603, and an optional user input 675. Processing logic630 is configured to drive images onto display 310 for viewing by a userof an HMD. Processing logic 630 is configured to receive scene images648 from camera 347. The scene images include images of the externalenvironment of the HMD. Processing logic 630 is also configured toreceive virtual images 649 from media store 603. Media 603 may be acomputer readable storage medium such as a computer memory, a streamingbuffer, or otherwise. Processing logic 630 may be configured to generatehybrid images by augmenting virtual images 649 based at least in part onthe scene images 648 of the external environment of the HMD captured bythe camera 347. For example, if an object in physical space is capturedby camera 347, a faint outline of that object (e.g. couch or table) maybe incorporated into the virtual images 649 to give an HMD user a senseof her surroundings with a hybrid image or a series of hybrid imagesthat includes the virtual image(s) 649 augmented based at least in parton the scene image(s) 648. Processing logic 630 may then drive thehybrid image(s) 683 onto display 310.

In an embodiment, an HMD includes a user input 675. User input 675 maybe a touch interface, a button, a switch, or otherwise. User input 675is configured to generate an input signal 634 when user input 675 isactivated by a user of an HMD. Processing logic 630 is coupled toreceive input signal 634 from user input 675. Processing logic 630 maybe configured to drive scene images 648 onto display 310 when inputsignal 634 is received by processing logic 630. In an example context,an HMD user has the HMD secured on his head and his eyes are covered bythe HMD. The HMD user is offered a physical object and activates userinput 675. Processing logic 630 may then render scene images 648 todisplay 310 so the user need not remove the HMD to interact with aphysical object. Rather, the scene images 648 are presented on display310. Since the scene images 648 are captured from a virtual pupilposition by camera 347 that simulates the user's actual pupil positionwith respect to scene light, the user may properly interact with thephysical object (e.g. grasp the physical object), even if the physicalobject is in a near-field physical object.

Embodiments of the invention may include or be implemented inconjunction with an artificial reality system. Artificial reality is aform of reality that has been adjusted in some manner beforepresentation to a user, which may include, e.g., a virtual reality (VR),an augmented reality (AR), a mixed reality (MR), a hybrid reality, orsome combination and/or derivatives thereof. Artificial reality contentmay include completely generated content or generated content combinedwith captured (e.g., real-world) content. The artificial reality contentmay include video, audio, haptic feedback, or some combination thereof,and any of which may be presented in a single channel or in multiplechannels (such as stereo video that produces a three-dimensional effectto the viewer). Additionally, in some embodiments, artificial realitymay also be associated with applications, products, accessories,services, or some combination thereof, that are used to, e.g., createcontent in an artificial reality and/or are otherwise used in (e.g.,perform activities in) an artificial reality. The artificial realitysystem that provides the artificial reality content may be implementedon various platforms, including a head-mounted display (HMD) connectedto a host computer system, a standalone HMD, a mobile device orcomputing system, or any other hardware platform capable of providingartificial reality content to one or more viewers.

The term “processing logic” (e.g. 630) in this disclosure may includeone or more processors, microprocessors, multi-core processors,Application-specific integrated circuits (ASIC), and/or FieldProgrammable Gate Arrays (FPGAs) to execute operations disclosed herein.In some embodiments, memories (not illustrated) are integrated into theprocessing logic to store instructions to execute operations and/orstore data. Processing logic may also include analog or digitalcircuitry to perform the operations in accordance with embodiments ofthe disclosure.

A “memory” or “memories” described in this disclosure may include one ormore volatile or non-volatile memory architectures. The “memory” or“memories” may be removable and non-removable media implemented in anymethod or technology for storage of information such ascomputer-readable instructions, data structures, program modules, orother data. Example memory technologies may include RAM, ROM, EEPROM,flash memory, CD-ROM, digital versatile disks (DVD), high-definitionmultimedia/data storage disks, or other optical storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, or any other non-transmission medium that can be usedto store information for access by a computing device.

Communication channels may include or be routed through one or morewired or wireless communication utilizing IEEE 802.11 protocols,BlueTooth, SPI (Serial Peripheral Interface), I²C (Inter-IntegratedCircuit), USB (Universal Serial Port), CAN (Controller Area Network),cellular data protocols (e.g. 3G, 4G, LTE, 5G), optical communicationnetworks, Internet Service Providers (ISPs), a peer-to-peer network, aLocal Area Network (LAN), a Wide Area Network (WAN), a public network(e.g. “the Internet”), a private network, a satellite network, orotherwise.

A computing device may include a desktop computer, a laptop computer, atablet, a phablet, a smartphone, a feature phone, a server computer, orotherwise. A server computer may be located remotely in a data center orbe stored locally.

The processes explained above are described in terms of computersoftware and hardware. The techniques described may constitutemachine-executable instructions embodied within a tangible ornon-transitory machine (e.g., computer) readable storage medium, thatwhen executed by a machine will cause the machine to perform theoperations described. Additionally, the processes may be embodied withinhardware, such as an application specific integrated circuit (“ASIC”) orotherwise.

A tangible non-transitory machine-readable storage medium includes anymechanism that provides (i.e., stores) information in a form accessibleby a machine (e.g., a computer, network device, personal digitalassistant, manufacturing tool, any device with a set of one or moreprocessors, etc.). For example, a machine-readable storage mediumincludes recordable/non-recordable media (e.g., read only memory (ROM),random access memory (RAM), magnetic disk storage media, optical storagemedia, flash memory devices, etc.).

The above description of illustrated embodiments of the invention,including what is described in the Abstract, is not intended to beexhaustive or to limit the invention to the precise forms disclosed.While specific embodiments of, and examples for, the invention aredescribed herein for illustrative purposes, various modifications arepossible within the scope of the invention, as those skilled in therelevant art will recognize.

These modifications can be made to the invention in light of the abovedetailed description. The terms used in the following claims should notbe construed to limit the invention to the specific embodimentsdisclosed in the specification. Rather, the scope of the invention is tobe determined entirely by the following claims, which are to beconstrued in accordance with established doctrines of claiminterpretation.

What is claimed is:
 1. A head mounted display (HMD) comprising: adisplay configured to provide display light to an eyebox area; areflective layer having a first reflective surface disposed opposite asecond reflective surface, wherein the first reflective surface isconfigured to receive the display light from the display and redirectthe display light to the eyebox area; and a camera, wherein the secondreflective surface is configured to receive scene light from an externalenvironment of the HMD and redirect the scene light to the camera forcapturing scene images, the camera positioned a first distance from thesecond reflective surface that is approximately the same as a seconddistance between the first reflective surface and the eyebox area. 2.The HMD of claim 1 further comprising: processing logic configured todrive hybrid images onto the display, wherein processing logic isconfigured to generated the hybrid images by augmenting virtual imagesbased at least in part on the scene images of the external environmentof the HMD captured by the camera, the processing logic configured toreceive the scene images from the camera.
 3. The HMD of claim 1 furthercomprising: a user input configured to generate an input signal whenactivated by a user of the HMD; and processing logic coupled to receivean input signal from the user input, wherein the processing logic isconfigured to drive the scene images onto the display when the inputsignal is received from the user input.
 4. The HMD of claim 1 furthercomprising: at least one lens element configured to focus the displaylight to the eyebox area, the at least one lens element disposed betweenthe reflective layer and the eyebox area.
 5. The HMD of claim 1, whereinthe reflective layer is angled approximately 45 degrees in relation tothe display and approximately 45 degrees in relationship to the camera.6. The HMD of claim 1, wherein the camera provides a virtual pupilposition that is approximately the same as a position of the eyeboxarea.
 7. A device comprising: a display configured to provide displaylight to an eyebox area; a reflective layer configured to receive thedisplay light from the display and redirect the display light to theeyebox area; and a camera, wherein the reflective layer is configured toreceive scene light from an external environment of the device andredirect the scene light to the camera for capturing scene images, thecamera positioned a first distance from the reflective layer that isapproximately the same as a second distance between the reflective layerand the eyebox area.
 8. The device of claim 7 further comprising:processing logic configured to drive hybrid images onto the display,wherein processing logic is configured to generated the hybrid images byaugmenting virtual images based at least in part on the scene images ofthe external environment of the device captured by the camera, theprocessing logic configured to receive the scene images from the camera.9. The device of claim 7 further comprising: a user input configured togenerate an input signal when activated by a user of the device; andprocessing logic coupled to receive an input signal from the user input,wherein the processing logic is configured to drive the scene imagesonto the display when the input signal is received from the user input.10. The device of claim 7 further comprising: at least one lens elementconfigured to focus the display light to the eyebox area, the at leastone lens element disposed between the reflective layer and the eyeboxarea.
 11. The device of claim 7, wherein the reflective layer is angledapproximately 45 degrees in relation to the display and approximately 45degrees in relationship to the camera.
 12. The device of claim 7,wherein the camera provides a virtual pupil position that isapproximately the same as a position of the eyebox area.
 13. A headmounted display (HMD) comprising: a display configured to providedisplay light to an eyebox area; a reflective layer positioned toreflect scene light of an external environment of the HMD; and a cameraoriented to capture scene images of the scene light reflected from thereflective layer, wherein the camera is positioned a first distance fromreflective layer that is approximately the same as a second distancebetween the display and the eyebox area.
 14. The HMD of claim 13 furthercomprising: a support member for supporting the camera, wherein thesupport member is attached to the HMD and extends away from the HMD. 15.The HMD of claim 13, wherein the display is configured to provide thedisplay light from a frontside of the display, and wherein thereflective layer is disposed on a backside of the display that isopposite of the frontside of the display.
 16. The HMD of claim 13,wherein an imaging field of the camera is substantially the same size asthe display.
 17. The HMD of claim 13, wherein a pixel plane of thedisplay is parallel to a plane of the reflective layer.
 18. The HMD ofclaim 13 further comprising: at least one lens element configured tofocus the display light to the eyebox area, the at least one lenselement disposed between the display and the eyebox area.